Wireless telecommunications service continues to evolve over time. When first introduced, wireless service employed analog radio technology that allowed users to send and receive voice calls. Most wireless service providers now employ digital communications technology to allow users to communicate both voice and data. In an effort to advance the state of wireless communications, a consortium of wireless service providers and equipment manufacturers has proposed a new specification for a wireless network architecture, known as the “Universal Mobile Telephone System” (UMTS) that affords broadband, packet-based communication of text, data and even multimedia services at relatively high speeds. Document 3GPP TS 23.101 V4.0.0 (2001-04) published by the 3d Generation Partnership Project (3GPP), Sophia Antipolis, Valbone, France, and known to those skilled in the art as the UMTS specification, represents an advance over the Global Standard for Mobile (GSM), a wireless telecommunication standard used throughout the world.
The UMTS specification proposes a core network that includes a circuit switched domain for providing voice service and packet-switched domain for providing General Packet Radio Service (GPRS). Packets enter and exit the packet domain, via one of a plurality of radio access networks. Each radio access network includes one or more wireless base stations managed by a radio network controller (RNC). Within the packet domain, each of a plurality of Serving GPRS Service Nodes (SGSN) controls access to a core network from a corresponding one of the radio access networks by identifying and authenticating the mobile terminal users seeking to send and receive packet data. After identifying and validating a mobile terminal user, the SGSN establishes a link to a Gateway GPRS Service Node (GGSN). To the extent that the mobile terminal user requires an IP address, as occurs when the mobile terminal user first accesses the network, the GGSN will assign such an address. For mobile terminal users that already have an assigned IP address, the GGSN will act as a server to route communications between the mobile terminal user and an external network to which the user has sought access.
Under the presently proposed UMTS standard, a mobile terminal user seeking to exchange packets with another mobile terminal served by the same or a different access network always must establish a relationship with the GGSN in the user's packet domain since the GGSN has the responsibility of routing IP traffic between mobile terminal users. Thus, all packet communications among two or more users, especially those in a common packet domain, (i.e., a common Public Land Mobile Network), occurs through the GGSN, even if the users do not need access to an external IP network. Accordingly, packet communications among mobile terminals users will likely place a burden on the GGSN, leading to inefficiency. General Packet Radio Service implemented within a GSM network in accordance with the GSM/GPRS 2.5G standard utilizes an architecture similar to that proposed for UMTS, and thus likewise suffers from the same inefficiency.
Thus, there is a need for technique for efficiently communicating packets among mobile terminal users that overcomes the disadvantages of the prior art.